UHF electronic tuner

Abstract

An RF input tuning circuit in a UHF electronic tuner uses a semicoaxial resonant cavity circuit which feeds amplifier and other tuning circuits not of the semicoaxial type, such as lumped constant or strip-line types.

What we claim is: 
     
       1. An ultra high frequency electronic tuner for tuning and heterodyning a desired radio frequency signal from among a possible plurality of radio frequency signals received from an antenna, said tuner comprising: a circuit board, a conductive tuner case surrounding said circuit board, a slender metallic bar mounted on said circuit board and forming a resonant cavity between itself and a wall of said tuner case, said resonant cavity being a resonant cavity radio frequency input circuit, an antenna coil for receiving radio frequency input signals, said antenna coil being disposed in said tuner case and being electromagnetically coupled to said slender metallic bar, at least one other resonant circuit disposed on said circuit board for tuning an output of said resonant cavity and being of a type other than a resonant cavity circuit. 
     
     
       2. An ultra high frequency electronic tuner for tuning and heterodyning a desired radio frequency signal from among a possible plurality of radio frequency signals received from an antenna, said tuner comprising: a circuit board, a conductive tuner case surrounding said circuit board, a slender metallic bar mounted on said circuit board and electromagnetically coupled to said antenna, said metallic bar forming a resonant cavity between itself and a wall of said tuner case, said resonant cavity being a resonant cavity radio frequency input circuit, and at least one other resonant circuit disposed on said circuit board for tuning an output of said resonant cavity and being of a type other than a resonant cavity circuit.